1. Field
The following description relates to a depth sensing apparatus and method that may acquire a depth image of a target object.
2. Description of the Related Art
A method of obtaining distance information from a sensor to an object may generally be classified into an active method and a passive method.
The passive method may be implemented by a stereo camera by calculating a distance from an object using only image information, instead of emitting light.
The active method may be implemented using a triangulation scheme of calculating a distance using a time of flight (TOF) and a triangulation. The TOF may measure a travel time of light by emitting the light towards an object and sensing the light reflected from the object, and the triangulation may sense a position of reflected light, the light being emitted by a laser positioned within a predetermined distance from a sensor.
In the case of the active method, because the light is directly emitted, it is possible to acquire a distance value in all the pixels of a sensor and thus, it is possible to provide a dense depth map. However, when background light is strong, distortion may occur in a depth value, because both the emitted light and the background light enter the sensor.
In addition, in the case of the active method, an error may occur. For example, if a pixel is saturated due to the background light, an accurate depth value may not be obtained. To increase a pixel's capacity, a size of a storage capacitor may be increased. However, an increased capacitance may result in a degradation of a space resolution and fill factor of the pixel. Accordingly, other methods of avoiding pixel saturation are being studied.